Detection and segmentation of wire-like structures is a challenging problem with many practical applications in both medical imaging and computer vision. An example of such an application is the detection and segmentation of a guidewire from fluoroscopic images used during coronary angioplasty. Coronary angioplasty is a medical procedure used to restore blood flow through clogged coronary arteries. During this minimally invasive procedure, a catheter containing a guidewire is inserted through an artery in the thigh and guided by the cardiologist until it reaches the blocked coronary artery. Then, a catheter with a deflated balloon is inserted along the wire and guided so that the balloon reaches the blockage. At that point, the balloon is inflated and deflated several times so as to unblock the artery. A device called a stent is often placed at that position in order to keep the artery from getting blocked again.
Throughout the procedure, the cardiologist uses fluoroscopic images to monitor the position of the catheter, guidewire, balloon and stent. Fluoroscopic images are x-ay images collected at a rate of several frames per second. In order to reduce the patient's exposure to x-ray radiation, the x-ray dosage is kept low and as a result, the images tend to have low contrast and include a large amount of noise.
As FIG. 1 illustrates, it is often very hard to distinguish the objects of interest, in particular the catheter and guidewire, as shown by images 102-106. The guidewire 108-112 in each image 102-106 is very difficult to detect and could easily be mistaken for part of the anatomy of the patient. Known methods for navigation of the guidewire use a magnet for tracking the guidewire.
Other known methods for guidewire detection use filtering techniques to enhance the guidewire. Some methods report the results as a set of pixels while other methods use splines to model the wire, but only concentrate on the wire tip which has much better visibility than the guidewire. Methods using a set of pixels use a Hessian filter with the purpose of adaptive filtering for image quality enhancement. There is a need for a method for automatically detecting and tracking a guidewire which can enhance the visualization quality of the fluoroscopic data while minimizing the exposure of a patient to x-ray radiation.